Right, while I'm on a role, heres another little conundrum to get yer teeth into.

Cornwall, so I've always been reliably informed, gets its name from the Cornish ''Kern''(horn) and Anglo-Saxon ''Wealas'' (foreigners) to give a hybrid name of ''Kern-wealas'', later shortened to''Cornwall''.

''Cornouaille'',in Brittany, is said to derive its name from Cornwall, UK, and was bestowed upon it by refugees from these isles fleeing the Saxon advance. Now, if you're fleeing a hated enemy and cross the sea to escape persecution, why in Gods name would you choose to saddle your new home with a label bestowed upon you by the very people you're escaping from? Surely ''Cornouaille'' should logically have been called ''Kernow''? Or does, as I suspect,''Cornwall/ouaille'' have a different derivation from the one traditionally offered?

The Breton name for Cornouaille is Kerne or Kernev, so the Bretons named it after Kernow (which they call Kernev-Veur, or Great Cornwall), the French after Cornwall (at least that is my understanding, probably not right)

The final V of Kernev is spoken like a -w ending. Kernow + wealas = Cornwall, first found as Cornwalas in 891 AD. The Anglo-Saxon 'wealas' hasn't affected the name Kernow - it just created the -wall addition and, of course, Wales. We have that great place-name from the Ravenna Cosmography (written c.700 AD from sources of c. 400 AD): Durocornovio (identified with Tintagel - the Latin V is W). In today's Cornish that would be Din Kernowyon.
The 6th century Dumnonian king Constantine is mentioned in a Welsh source as 'Custennin Gorneu', and then we have the British Easter Annals which in 875 AD recorded the death of Donyarth, 'rex Cerniu'. The spelling Kernow is first found c. 1400.
Very few places in Britain have variant names in other languages, but Cornwall does: French - Cornouaille; Spanish - Cornualles; Italian - Cornovaglia; Irish - Corn na Breataine; Welsh - Cernyw; Breton - Kernev Veur. Someone gave me the Polish name but I can't find that for the moment, and there's a Scots Gaelic one, too. Rather more importance than those countries would give to a mere "c*unty", you might note.
Dumnonians (Cornwall was the western part of that kingdom) didn't colonise Brittany in the 5th century (allegedly under the king Conan Meriadoc) to escape the Anglo-Saxons - they didn't affect us for several hundred more years. They also colonised Galicia at about the same time. Why has always been a mystery, but I've a theory which Prof. Barry Cunliffe likes.
The Romans interrupted the Atlantic sea-trading which had gone on from Neolithic times, replacing it with cross-Channel stuff controlled by themselves. Their withdrawal from Britain in 410 AD, and the subsequent quick collapse of the Western Roman empire. I think that Dumnonians then colonised Brittany and Galicia c.450 AD to control the Atlantic trade routes from the two most strategically placed coastal areas on that route. We know from finds of Mediterranean ware at Tintagel, Glastonbury, South Cadbury Castle and other places that the Atlantic trading was up and running again before 500 AD.

Polish for Cornwall is Kornwalia. Wales is Walia.
When I was in Poland I found that people had no problem understanding the link between Cornwall and Wales, probably because "walia" is part of the word for Cornwall. If Cornwall were (still) Cornwales the English would probably have a better idea as well.

Thanks. That must be one of the most pronounceable words in Polish!
I remember having my eyes tested. The optician said: 'Can you read the bottom line on the card?" I said: 'If I was Polish, I could pronounce it!"

Carbilly said:
I've always thought that the Breton name for Cornwall is ''Kerno'', and thats what makes up the last element in the Breton port of Con-carneau.

No, that is French. The Breton name of the town in question is Konk-Kernev (or Konk-Kerne, the final -v having been dropped in pronunciation as well as spelling in many varieties of Breton).
Even in French, the pronunciation of <eau> as [o] is comparatively new. At the time when the placename was absorbed into French, <-eau> did not stand for [-o] but for [-ɛw]. So what they tried to represent at the time was something much closer to the Breton pronunciation.

No, that is French. The Breton name of the town in question is Konk-Kernev (or Konk-Kerne, the final -v having been dropped in pronunciation as well as spelling in many varieties of Breton). But if what Marhak says is correct, (and I have no reason to doubt his word) the final 'V' is/was sounded as a 'W' anyway, making it Con-Kernow in French or Breton?

I was not contradicting what Marhak wrote. The Breton word Kerne(v) is indeed a cognate of Kernow. But that was not the point of my post. I was trying to point out that the first part of the Breton placename is Konk, ending in a k, not Con or Kon, and that French orthography hides the fact that <eau> originally did not represent today's pronunciation as [o]. Konk-Kernev ended up spelt as Concarneau because that was the closest approximation possible using Middle French orthography.
Whether or not there is a [-w] (spelt <v>) at the end of the second part depends on the variety of Breton we are talking about. Most have dropped it today, but historically it is of course there. For the purpose of disambiguation, (insular) Cornwall is referred to as Kerne(v) Veur, Great Cornwall, in Breton today.

@nige999: The Breton form of the placename is Rostren, pronounced rosh-TRENN (stressed on the second syllable; [roʃ'trɛn]) in the south-east of the Breton speaking area and ROSS-tran (stressed on the first syllable; ['rostrən]) in much of the rest.

There are major differences between the Welsh and Breton situations:
Those Breton speakers that remain today largely consist of two groups which do not interact much with one another. There's about 20.000 (younger) activists who are proud of the language and tend to use it publicly but are not normally native speakers. Their Breton sometimes sounds so French that it is difficult to recognise for somebody who is not familiar with the language. And then there's about 200.000 native speakers, mostly over the age of 60, who do of course speak Breton without a French accent, but who on the other hand are the very generation that is so ashamed of their language that they decided not to pass it on to their children. They will normally not let outsiders hear them speak it.
It is also a question of where you are. There are some regions where you are still more likely to hear Breton spoken in everyday situations, especially in places where bilingual schooling is more strongly developed than elsewhere and where young, uninhibited speakers make themselves noticed.

It is such a shame that Celtic speakers, In Brittany, Cornwall, Wales and other places were made to feel (by the majority language neighbours) that their language was somehow inferior. We know from Scawen that this was one of the reasons for the demise of Cornish and, indeed, Nicholas Boson's own mother forbade him to speak Cornish when he was a child. Then there are the early C20 accounts of Welsh-speaking children being humiliated in their schools if they were caught speaking Welsh.
It's still not that good here, either. A Cornish dialect or accent is the mark of a 'thicko' according to some and today's Cornish children aren't using it (why isn't Cockney treated that way?). A Cornish kid can't be Cornish either - we have that true tale of a child coming home in tears because she'd insisted she was Cornish and had the teacher screaming at her that there was no such thing. She was English! And that disgrace was within the last 10 years.

Two videos to illustrate my point about native speakers' and learners' Breton a little:

1 - Two native speakers of Leoneg (north-western group of dialects):
http://pellwolok.kernewegva.co....._ven_1.mp4

2 - The evening news in Breton, read by and featuring learners with heavy French accents. As I said, I believe that it would be difficult for the casual listener to notice that they are not, in fact, speaking French.http://www.youtube.com/watch?v.....FSqMu-zBkY